Audio problem: When Phoebe hits Cole over the head in the courtroom, the sound of something unfreezing is heard, but Cole wasn't frozen and Piper doesn't unfreeze the room until a few moments later.
Audio problem: When Prue is at the dentist, she grabs a guy and he says, "What, what did I do?" to his girlfriend, but his lips do not move.
Sleuthing With the Enemy - S3-E8
Audio problem: When Phoebe fights with Krell in the mausoleum, the vial containing the Belthazor vanquishing potion is heard smashing, but after Krell is vanquished, Phoebe picks up an unsmashed vial and uses it to stage Cole's escape.
Audio problem: When Evil Prue flings Piper and Phoebe back, you see Piper hit a pillar, but with Phoebe's voice of pain. When we see Phoebe fall behind a structure, we hear Piper's voice of pain.
Answer: That was a mistake in the series.
Also, the episode is called 'Babies First Demon' and this alone tells us that it's Wyatt's first time in the field (so to speak) and as the sisters say, they've done a good job of clearing up their own magical messes so far. Nobody really knows how advanced Wyatt's powers are, or will become. That's why the cleaners appear, to nip things in the bud. The Cleaners didn't want to chance that the sisters could clean Wyatt's magic up, just incase they couldn't. Therefore intervening themselves, just in case.